Internal-combustion engine



: Dec. 14, 1926.

F. M. CAMPBELL INTERNAL COMBUSTION ENGINE Filed Nov. 27. 1923 mam/1111111 In ere/a I" 7 I. M Cain 0 Patented Dec. 14, 1926.

inane FRANK IVIONTGOMERY' CAMPBELL, OF DUNEDIN, OTAGO, NEVT ZEALAND.j

INTERNAL-COMBUSTION ENGINE.

Application filed November 27, 1923. Serial No. 677,3195.

The object of the invent-ion 'is to improve the method of introducing fuel and provide apparatus therefor, whereby scavenging is rendered more efiicient and a higher percentage of useful work obtained fromthe engine.

, According-to this invention the fuel mixture is admitted throughan overhead port in the cylinder cover, rendering more effi- 1 cient scavenging and less wastage of fuel through the exhaust port; each fresh charge of fuel is brought into contact with a sparking plug, thus reducingits liability to heat, and reducing the very high temperature to which cylinder heads of engines working on the two strokecycle are liable; by passing the mixture into the cylinder in this manner the burnt gases do not collect in the cylinder head so readily witha tendency to retard flame propagation, causing consequent loss of power.

By admitting the gases to the crankcase through a rotary valve, the charge has a longer period in which to be drawn in, and is not subject to the restricted control by the movement of thepistonas'inthe ordinary-two cycle engine, wherethe inletport to the crankcase is only open-for a very short period, and is also open for a time-when the piston connnences'to com-press the gases in the crankcase.

Thusthis engine, with the adaptation of a small amount of four-cycle engine practice, has combined in it the better qualities of the two types, and in so doing there will be a consequent saving of fuel over that consumed by other engines of the same bore, stroke, and piston speed.

This engine can be used'in units-of two, four, or more cylinders, in line with, but with a slight rearrangement of the valve gear giving the engine a similar appearance to the present four, six, and straight eight cylindered engines working on the four-stroke cycle. At the same time it will give a smaller and more powerful engine and a more even torque for the same number of cylinders and cylinder capacity.

In the drawings accompanying: the specification,

Figure 1 is an elevation, the middle part broken away of the engine, the crank case in section, the top of the cylinder and a portion of the induction pipe beingein' section.

Figure 2 is an elevation, partly in section, of Figure 1, looking inthe direction of the The usual parts employed in internal conr bustion engines are included in my appara tus; namely, a cylinder 1. crank case 2, and crank shaft 3. The crank case 2, is proton ably in two parts 2* and 2 and adapted to be bolted. together as indicated at 4. There is a cover 5, for-the magneto drive 7s 6 and 7, and valve operating-cam 8; the said cover 5 fits upon the face of the crank case forming a joint therewith at 9, being adapted to be secured to the said face by suitable studs, some of which are indicated at 10.

There is a crank shaft aperturecl bush 11. adapted to be-a press .it into part 5 of the cover 5, the said bushis a-p .rturcd at 19 to form communication between the carburetor and the cylinder 1, through the medium of the hollow portion 18, of the crank shaft 8; a portion of the feed pipe leading from the carburetor to form tl'ie communication above stated is indicated. in Figure 3 at 14:. c

There is a boss piece 15 projecting to the interior from the face of the cover 5, and a portion 15 of the said boss 15 proje ing outwardly to housea'spindle 16 projecting .from'thc magneto drive spurpinion (i; the'said spindle projects outwardly sat. ciently to engage the gear, as indicated at 17, for a direct driveon to the magneto (not shown) and which is secured preferably in the manner indicated at li.

There is a push rod. lifter spindle 18 threaded to register with a threaded hole in thecrank case having its end projecting sufliciently to engage with the rod lifter, which is fashioned at 19, to engage with the cam 8, the upper face of the lifter 1.9 being adapted to engage with a point of the push rod 20, the said push rod projecting through a hushed boss part in the crankcase at 21.

The cam 8 preferably integral. with the magneto drive spur pinion]? on the crank shaft 3, both parts being keyed thereto, in a position for the gear tomesh with the gear pinion 6. The crank shaft is pretcrably ofthe form indicated, having one of its journals hollow, as at 13, and adapted to projeetthrough a portion of the cran: casing and journal in the bearing bush 22 and insthe apertu red bush 11', fitted in the cam gear cover part 5. 23 in the crank shaft to register with the aperture 12 in the apertured bush 11, once in the course of the crank shafts revolution, tlius forming communication between the carburetor and the interior of the crank shaftcase.

There is an aperture 2% in the part 2 of the crank case 2 into which fits one end of the induction pipe 25, there being tapped holes to register with screws 26 for the purpose of studding the said induction pipe to the crank case.

The cylinder is liiolted to the top face of the crank case, and is fitted with the usual type piston, not shown in the drawings; the cylinder is fashioned at the top preferably in the manner indicated, having the inlet valve 27, open or set concentric with and directly over the top of the piston. Ignition is introduced through the usual medium, a sparking plug, the position of the said plug being provided for as indicated at 23, while diametrically opposite, provision is made for compression release valve. the body part being threaded to register with a standard sparking plug thread so that the said release valve body and the sparking plug may be interchangeable.

The induction pipe is preferably in two parts, coupled in a convenient manner, the upper portion 25 which projects hori zontally towards the centre of the cylinder, is provided with a machined face to form a joint. with a machined face on the cylinder head 1, the inlet port 29 on the induction pipe being so arranged that, when a joint with the cylinder head 1 is formed, the pipe will be concentric with the inlet aperture in the cylinder head. Immediately above the said concentric apertures there is a boss 30, projecting partially inwardly from the surface to the interior part of the induction pipe, and partially outwards from the exterior surface of the induction pipe through which a hole is bored concentric with the before mentioned inlet port. There is a lmsh 31 fitted to the hole to form a guide for the stem 27" of the inlet valve 27, the said valve being spring maintained in the closed position against its seat 27.

There is an upwardly projecting bracket member 32, formed integral with the upper part 25 of the induction pipe 25, for the purpose of supporting the rocking lever 33 which is pivctally mounted on the spindle ill. between the lugs 35 of the said upwardly projecting bracket Motion to open the valve is transmitted through the medium of the cam 8 once in each revolution of the crank shaft; the said cam engages the push rod lifter 19 which is held normally in contact with the'tread of the cam under spring influence. The push rod lifter 19 engages with the point of the push rod 20, and upon There is an inlet: port the cam 8 rotating, the enlarged portion 3 of the cam 8 comes in contact with the push rod lifter raising the said push rod 20, turn-- ing the member 33 upon its pivot 34:, and depressing the inlet valve 27. There is an adjustment consisting of a stud 36 having enlarged portions 37 to take the top end of the push rod 20, and a ball member 38 to reduce friction; the said stud is threaded. and adapted to screw into the rocking lever 33 for adjustment and be secured there by at am nut. A spent outlet. or exhaust port is provided for, not shown in the drawings.

On proceeding to describe the cycle of operations, I will assume that the engine is working, and that ignition has exploded a compressed charge On the downward stroke of the piston a charge is drawn into the crank case through the port 23; in the progress of the cycle, the inlet valve 27 is opened due to they influence of the cam 8, on the crank shaft rotating, and in a measure the port 23 opens simultaneously with the opening of the said inlet valve, permitting partially compressed charge of fresh fuel to be drawn into the cylinder and approximately at the same time a fresh charge of fuel drawn from the main supply through the pipe let, to the crank case.

On the piston descending, due to explosion of the fuel, the spent gas or exhaust port is opened and the burnt gases expellel. the return stroke of the piston compressing the charge within the cylinder, having at an early part of its return stroke partially compressed the charge in the induction pipe, and in the crank chamber, before it reaches the cylinder. Thus there is induction, compression and explosion every revolution.

What I claim as new and desire to secure by Letters Patent is In a two-cycle internal combustion cugine, a cylinder, a head removably secured thereon, a fuel inlet in the head, a crank shaft, a two-part crank cascthrough which the crank shaft extends, one side wall of the crank case being fOlHiGCl with a flange to define a chamber in part concentric with the crank shaft and extending transversely of the crank case to receive engine operating parts actuated by the crank shaft, a cover for said chamber having a hollow extension in line with the crank shaft, and acommunication leading from the interior of said extension to the fuel inlet, said crank shaft being hollow for a portion of its length in cluding that part within the extension and being formed with an outlet from said hollow portion o communicate with said coinmunication leading to the fuel inlet.

In witness whereof I affix my signature.

' FRANK MONTGOMERY CAMPBELL. 

